Apparent inhibition of pyruvate kinase by arginine phosphate a problem of kinetic studies on partially purified extracts

Studies on the apparent inhibition of the type-M pyruvate kinase from Carcinus maenas (the common shore crab) by phospho-l-arginine

“…AU these observations are the result of ADP depletion via a second reaction involving arginine kinase and phosphoarginine. This directly confirms the suggestion of de Zwaan & Ebberink (1978). lactate dehydrogenase reaction (Biicher & Dfleiderer, 1955) in the presence of 25 rnM-Tris/HCl (pH 7.4), 8 mM-M$ie and 1 mM-EGTA; 100mM-KCI was added, except where noted.…”

“…In many invertebrate species the equivalent phosphagen is phospho-L-arginine, and this has been reported to inhibit pyruvate kinase in crude extracts of Oplophorus gracilirostris (Guderley et al, 1976) and Helix pomatia (Wieser & Lackner, 1977). Studies on crude extracts of Mytilus edulis (de Zwaan & Ebberink, 1978) led to the suggestion that the inhibition observed is only an apparent inhibition, possibly owing to a side reaction involving arginine kinase present in the crude tissue extracts used.…”